1. Field of the Invention
This invention relates to model airplanes and more particularly relates to an instrument for determining the angle of attack or incidence of a wing or horizontal stabilizer-elevator, the amount of wash-out or wash-in in a wing or tail and the angle of engine thrust in a model aircraft.
2. The Prior Art
In constructing a flying model aircraft, it is well known that certain parameters are critical in determining the flight characteristics of the aircraft and, in fact, determining whether or not the aircraft will fly at all. For example, the wing of an aircraft must have a positive angle of attack or incidence in order for it to fly. Other critical parameters are the angle of attack or incidence of the horizontal stabilizer-elevator, the amount of wash-out or wash-in of the wing or tail and the thrust angle of the engine.
Heretofore, there has been no instrument for conveniently obtaining a measurement of these critical parameters either during construction of the model aircraft or for diagnosing the problems with model aircraft which are malfunctioning. The procedures which have been employed have been cumbersome and time-consuming. For example, the method commonly in use for measuring the angle of attack or incidence of a wing involves the step of blocking or immobilizing the fuselage of the aircraft so that it is perfectly parallel to a work table, adjusting the wing so that it is perfectly parallel to the work table, adjusting the wing so as to impart a particular angle of incidence thereto, measuring the distance from the work table to the leading edge of the wing, measuring the distance from the work table to the trailing edge of the wing and computing the angle of incidence through well-known geometric relationships.
The following U.S. Pat. Nos. relate generally to the problem discussed above:
______________________________________ 1,494,722 Tingstrom et al 1924 2,402,567 Milner 1946 2,520,934 Hoy 1950 2,531,077 Mullin 1950 2,737,722 Keim 1956 2,770,967 Du Pont 1956 2,872,809 Yavne 1959 ______________________________________